Problem: $ { \left[\begin{array}{rr}{3} & {4} \\ {-1} & {-1}\end{array}\right]-\left[\begin{array}{rr}{1} & {-2} \\ {3} & {-2}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{3}-{1} & {4}-{-2} \\ {-1}-{3} & {-1}-{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{2} & {6} \\ {-4} & {1}\end{array}\right]}$